JLC 633

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Calibre 633 was a quartz watch movement with a mechanical chronograph developed by Jaeger-LeCoultre and also used by IWC.

Calibre 633 was a member of the Jaeger-LeCoultre Mechaquartz family. It was the most complicated movement in the family, with 27 jewels and an alarm function.

There are two motors in the calibre:

  • One powers the main timekeeping hands at a frequency of 1 Hz
  • A second powers the mechanical chronograph at 4 Hz

Since the chronograph is mechanical, it has the same feel as a conventional chronograph movement, including mechanical zero reset. Yet the Mechaquartz was much more compact than a conventional automatic chronograph movement.

Calibre 633 differed from Calibre 630 and 631 in that it included an alarm function.

Note: There is conflicting information on the quartz frequency, with some sources claiming dual 1 KHz and 4 KHz crystals and others claiming 32 KHz.


Calibre 633 was used in chronograph watches in the 1980's and 1990's, though not as widely as Calibre 631:

External Links




Quartz movement with mechanical chronograph


Hour, minute hands
Small seconds at 6:00
Chronograph with 30 minute and 12 hour subdials at 9:00 and 3:00, respectively


H 3.8 mm
D 23.3 mm
27 jewels
Frequency 32 KHz

Production period: